The object of the present invention is a crankcase lower part for a supercharged internal combustion engine having a liquid cooled intercooler and/or charge air intermediate cooler, the crankcase lower part enclosing the space below the crankshaft.
Internal combustion engines of the above-mentioned type typically have a cylinder head, a crankcase upper part and a crankcase lower part as the main components. The gas exchange valves, the injection nozzles, and the particular actuating devices are located in the cylinder head, which terminates the combustion chambers of the internal combustion engine on top. The cylinders having the pistons positioned therein and the crankshaft connected via connecting rods to the pistons are positioned in the crankcase upper part The crankcase lower part adjoining the crankcase upper part encloses the space below the crankshaft and comprises at least one oil sump used as a collection chamber for the engine oil. For reasons of stability, the crankcase lower part may be implemented in two parts in such a way that a yoke plate or a bearing plate is provided between crankcase upper part and oil sump. While the yoke plate is only used for reinforcing the crankcase upper part, the bearing covers for the crankshaft bearings are also molded onto the bearing plate, which is also referred to as a “bed plate”. An arrangement having a yoke plate is known, for example, from EP 0 663 522 Al, while EP 0 076 474 Al describes an arrangement having a bearing plate.
The terms cited above and in the related art: (crankcase) upper part and (crankcase) lower part, as well as statements such as “below the crank-shaft” etc. are not to be understood in a geodetic way in this context, but rather relate to the movement direction of the piston to the upper and/or lower dead center. Therefore, downward is in the direction in which the piston moves toward the lower dead center. This difference is important because the object of the present invention is applicable for internal combustion engines installed at any arbitrary angle of inclination.
As already noted, internal combustion engines of the type described above, particularly diesel internal combustion engines, are equipped with an arrangement for compressing the charge air; in this context one also refers to supercharging of the internal combustion engine. In this case, the supercharging may be single-stage or also multistage, particularly dual-stage. An internal combustion engine having dual-stage supercharging is known, for example, from DE 19961610. To reduce the charge air temperature, the arrangement described therein has an intercooler positioned after the first compressor stage as an intermediate cooler, whose object is to reduce the temperature level of the charge air already after the low-pressure stage, in order to thus increase the efficiency of the internal combustion engine and reduce the exhaust gas emissions. A further intercooler is typically positioned after the high-pressure compressor. It remains open how the intercoolers according to DE 19961610 are implemented.
In internal combustion engines of the type cited at the beginning positioned in vehicles, in addition to the problem of the required efficient cooling of the charge air, the problem exists that the amount of space available for installation is extremely small. Furthermore, for optimum throughput of charge air, it is required that the charge air be opposed with the smallest possible fluidic resistance.
It is therefore an object of the present invention to provide an intercooler which ensures efficient cooling of the charge air, takes the tight spatial conditions, particularly between low-pressure and high-pressure compressors, into consideration, and opposes the charge air with the smallest possible flow resistance.